Tissue graft compositions made of devitalized native tissues have been widely used to restore damaged or missing tissues inpatients. Typically these compositions are made from the extracellular matrix of tissues, for example, the submucosa of the intestine (SIS), or urinary bladder (UBS), and the epithelial basement membrane of, for example, the urinary bladder (UBM), SIS, UBS, and UBM are described in U.S. Pat. Nos. 6,576,265, 6,579,538, 5,573,784, 5,554,389, 4,956,178, and 4,902,508, each of which is incorporated in their entirety by reference herein. Collectively these compositions are termed extracellular matrices (ECMs).
These compositions alone generally have sufficient strength to be useful for aiding the restoration of tissues and organs that are not subjected to large forces or pressures. ECMs are typically used to repair tissues or organs at anatomic sites in the body that are different from the tissue or organ from which the ECM was derived.
Tissue graft compositions are sometimes layered. The layers include various ECMs which may be hydrated, dehydrated or lyophilized. The layers are mechanically compressed, vacuum compressed or “glued” to join one layer to the other to form the composition. Layering, in some cases, adds strength to the composition.
Restoration of tissues far which ECMs are used include epithelial tissues. Epithelial tissues have an epithelium. Restoration of epithelial tissues requires restoration of the epithelium and the underlying connective tissues layers of the epithelial tissue. Restoration of the epithelium occurs rapidly when the epithelial basement membrane is present. On the other hand, restoration of the connective tissue layers of epithelial tissues is slower than restoration of the epithelium, prolonging complete restoration of the damaged epithelial tissue.